There are circumstances in which provision of a tactical data processing device is vital. Such circumstances are, for example, when armed forces are engaged in a theatre of operation. In these circumstances each unit engaged must have equipment which is appropriate for its mission, and which is up-to-date.
In practice three installation methods are known above all.
A first method is the traditional method in which an administrative user installs the processing device by undertaking the following steps:                In an appropriate sequence, making the installation media of the various components required accessible in read mode; this relates in general to DVD disks, Blu-ray disks, removable disks, etc.        For each medium, executing an installation program present on the medium;        For each medium, answering the questions of the installation program.        For each medium, undertaking the configuration to make the application(s) installed by the medium usable.        
This first method therefore requires several media to be handled, and it also requires the attention of the user performing the initialization, who must answer correctly the questions posed to them by the installation program during the procedure. Many of these questions are specific to the IT field, and are unknown in the professional field of the person whom it is desired should undertake the initialization.
A second installation method consists in supplying, when possible, a file with answers to the questions. Such a file is associated with the installation program, which uses it as a set of parameters. The installation program then reads the answers to the questions in the file, which means that the user undertaking the installation does not have to do so.
Both these methods have major disadvantages. The first disadvantage is the fact of handling several media. This implies, in a potentially stressful environment, non-negligible risks of choosing the wrong medium, or of using the media in the wrong order.
It might be thought that this problem is simple to resolve: one need merely undertake an initialization once, and then create a binary image of the finalized initialization. All that would then be required would be to copy this binary image to the devices which must be initialized. However, the problem would only seemingly be resolved, since several images would have to be managed: one for each possible data processing device. I.e. one for each hardware configuration. This would therefore be equivalent to handling several media.
Once these solutions have been envisaged, it is found that their initialization times are too lengthy, in terms of the immobilization of the data processing device. It appears, after analysis, that the quantity of data which must be copied is very large: at least some ten Gigabytes which, depending on the performance of a communication interface, may represent as much as several hours of transmission.
The words installation and initialization are used. In this document an initialization is the action of making a device operational, i.e. of applying an initial configuration to it. An initialization of a device includes formatting of the storage system, and one or more installations of applications. Installation of a device does not necessarily imply formatting.